This invention relates to a simple apparatus for removing foreign material from an inside surface of a duct, such as a cylindrical duct carrying wood dust laden air or other fluids having foreign material entrained therein. Such dust or foreign material builds up on the inside surface of the duct increasing fluid flow resistance and potentially creating a fire hazard where the accumulation is flammable.
In a typical application of the apparatus of this invention, ducts transmitting fluid flow must be periodically cleaned, which is a labor intensive time consuming procedure. For example, in the wood and pulp industry, a duct is located above or adjacent the work area which removes wood dust laden air. Similarly, ducts commonly remove kiln or coal dust, paint and dust particles, etc. Such particles must be removed from the inside surface or surfaces of the duct to maintain the efficiency of the system.
Where the particulate material carried by the duct is flammable, such as wood or coal dust or paint particles, it is desirable to create a break in the fouling layer to prevent flame from propagating along the duct through the fouling layer. That is, it is very desirable in such applications to remove flammable particles from areas on the inside surface of the duct to create a dust free area or fire break which prevents propagation of flame through the duct. Further, a flow, pressure or temperature sensor may be rendered inoperative or inaccurate by fouling which must be removed from the duct wall.
The duct cleaning apparatus of this invention effectively removes foreign material from an inside surface of the duct where the apparatus is located and creates dust free areas preventing propagation of flame through the duct. Further, the duct cleaning apparatus may be utilized to continuously clean the area where sensors located within the duct.